The machine of this invention relates generally to the field of apparatus for cleaning the surfaces of articles such as metal castings and the like by throwing abrasive shot onto the surfaces of the articles as a batch of the articles are tumbled about in the path of the abrasive shot. Prior machines in this field have not been completely satisfactory either because the parts are not uniformly cleaned or the time and expense required to clean the parts has been too high. It is an object of the present invention, therefore, to provide an improved machine for blast cleaning the surfaces of parts.